1. Field of the Invention
The present invention relates to a technique of forming a solid object, and more particularly to a method of forming a three-dimensional object easily with high accuracy by stacking and gluing sheets together and to a sheet lamination modeling apparatus.
2. Description of the Related Art
Conventionally, in order to fabricate a three-dimensional model having a complicated configuration, there has been proposed a method of stacking paper sheets on which heat-melting adhesive has been applied beforehand.
In this method, after stacking sheets one on the other, the sheets are glued together by heating the sheets with a hot roller. Then, an upper sheet is cut along a contour of a region constituting the three-dimensional object to be obtained.
However, according to this method, it was difficult to stack and glue paper sheets together with high accuracy to thereby fabricate a three-dimensional object having sufficient adhesive strength without separation of stacked sheets.
Further, paper sheets are subject to deformation by the effects of pressure, humidity, or the like. Additionally, with a certain thickness of the adhesive layer between the paper sheets, it was difficult to control the thickness in one adhesive layer to be even or to control the thickness of each adhesive layer to be the same. Therefore, it was difficult to ensure high fabricating accuracy of the three-dimensional model.
As an alternative way to fabricate a three-dimensional model, there has been proposed a photo-solidification modeling method. However, this method requires a step of light exposure by using a photo-solidifying resin. Therefore, the initial cost for preparing the equipment for performing this method is high, and the formed surface needs alcohol cleaning. Further, a secondary solidifying process is required after forming a model in order to obtain a perfect polymerization, so that it was difficult to fabricate such a three-dimensional object in an ordinary office.
Therefore, the present invention provides a sheet lamination modeling method which can easily fabricate a three-dimensional object having sufficient strength without separation of stacked sheets.
Further, the present invention provides a sheet lamination modeling method which can fabricate a three-dimensional object having high accuracy.
Further, the present invention provides a sheet lamination modeling apparatus which can fabricate a three-dimensional object with high accuracy.
(1) A first aspect of the invention provides a method of forming a three-dimensional object by stacking and gluing sheets together, which comprises the steps of providing a lower sheet cut into an effective area constituting the three-dimensional object and a waste area not constituting the three-dimensional object, providing an upper sheet to be stacked on top of the lower sheet, the upper sheet having an effective area constituting the three-dimensional object and a waste area not constituting the three-dimensional object, supplying an adhesive between the lower sheet and the upper sheet and onto an area which extends outwardly of an overlapping area covering both the effective area of the upper sheet and the effective area of the lower sheet, thereby forming an effective adhesive layer, gluing the lower sheet and the upper sheet together, and cutting the upper sheet into the effective area and the waste area.
According to this method, the upper and lower sheets are glued together by supplying the adhesive onto an area larger than an area covering both of the effective areas of the upper and lower sheets (hereinafter referred to as an overlapping area). Thus, the upper and lower sheets are reliably glued together on the overlapping area, and a three-dimensional object having great strength without separation or deformation can be obtained with ease.
(2) A second aspect of the invention provides a sheet lamination modeling method according to the first aspect of the invention, which comprises the additional step of forming an auxiliary adhesive layer by supplying the adhesive less densely than the effective adhesive layer, onto the outside of the effective adhesive layer.
According to this method, with the auxiliary adhesive layer, the sheets can be supported during gluing and cutting operation. Thus, positional errors during gluing and cutting operation can be reduced and warps of the sheets can also be reduced.
(3) A third aspect of the invention provides a sheet lamination modeling method according to the first aspect of the invention,: wherein the adhesive is applied by electrostatic transfer.
According to this method, the adhesive can be applied by electrostatic transfer. Thus, it is possible to simply and easily fabricate a three-dimensional object in an ordinary office, and the amount and the position of the application of the adhesive can be set on a CAD system.
(4) A fourth aspect of the invention provides a sheet lamination modeling method according to the first aspect of the invention, wherein the upper sheet and the lower sheet are glued together under pressure.
According to this method, the effective adhesive layer (and the auxiliary adhesive layer) can be formed by pressurization. Thus, it is possible to make the lamination height of the object constant and to eliminate warps which may be generated on the stacked sheets. As a result, flatness of the stacked sheets can be secured and maintained, so that an object having sufficient accuracy can be obtained.
(5) A fifth aspect of the invention provides a method of forming a three-dimensional object by stacking and gluing sheets together, which comprises the steps of providing a lower sheet cut into an effective area constituting the three-dimensional object and a waste area not constituting the three-dimensional object, providing an upper sheet to be stacked on top of the lower sheet, the upper sheet having an effective area constituting the three-dimensional object and a waste area not constituting the three-dimensional object, supplying an adhesive between the lower sheet and the upper sheet, impregnating the adhesive into the upper sheet and the lower sheet under pressure, thereby forming a joined layer, and cutting the upper sheet into the effective area and the waste area.
According to this method, the adhesive is impregnated into both the upper and lower sheets by pressurization to form the joined layer through which the both sheets are tightly joined together. Thus, it is possible to eliminate fabrication errors which may be generated by the thickness of the adhesive layers, so that a three-dimensional object having high accuracy can be obtained.
Further, the impregnated adhesive forms the joined layer flat by pressurization at one time. Thus, it is possible to restrain warps or like defects of the sheets caused by moisture absorption, to thereby maintain flatness of the sheet lamination, and to secure the fabricating accuracy.
(6) A sixth aspect of the invention provides a sheet lamination modeling method according to the fifth aspect of the invention, wherein the adhesive is applied by electrostatic transfer.
According to this method, the adhesive is applied by electrostatic transfer, and thus, the amount and the position of the application of the adhesive can be easily controlled, so that a three-dimensional object having a complicated shape: can be obtained.
(7) A seventh aspect of the invention provides a method of forming a three-dimensional object by stacking and gluing sheets together, which comprises the steps of providing a lower sheet cut into an effective area constituting the three-dimensional object and a waste area not constituting the three-dimensional object, providing an upper sheet to be stacked on top of the lower sheet, the upper sheet having an effective area constituting the three-dimensional object and a waste area not constituting the three-dimensional object, supplying an adhesive between the lower sheet and the upper sheet, gluing the lower sheet and the upper sheet together under pressure, cutting the upper sheet into the effective area and the waste area, thereby forming a sheet lamination block including the three-dimensional object, and pressing the sheet lamination block until the adhesive interposed between the sheets of the sheet lamination block is hardened.
According to this method, the sheet lamination block is continued to be pressed even after completion of the stacking operation, so that generation of warps by hardening the adhesive interposed in the sheet lamination block is restrained. Thus, a three-dimensional object having high accuracy can be obtained with ease.
(8) An eighth aspect of the invention provides a method of forming a three-dimensional object by stacking and gluing sheets together, which comprises the steps of providing a lower sheet cut into an effective area constituting the three-dimensional object and a waste area not constituting the three-dimensional object, providing an upper sheet to be stacked on top of the lower sheet, the upper sheet having an effective area constituting the three-dimensional object and a waste area not constituting the three-dimensional object, supplying an adhesive between the lower sheet and the upper sheet, gluing the lower sheet and the upper sheet together under pressure, cutting the upper sheet into the effective area and the waste area, thereby forming a sheet lamination block including the three-dimensional object, melting the adhesive interposed between the sheets of the sheet lamination block, and hardening the melted adhesive.
According to this method, after completion of the stacking operation, the adhesive interposed between the sheets of the sheet lamination block is melted and then hardened. Unlike the case where the adhesive is hardened during the stacking operation, all the sheets are glued together by hardening the adhesive under a state of less thermal distortion, so that generation of warps in the whole finished three-dimensional object can be prevented. Thus, a three-dimensional object having high accuracy can be obtained with ease.
(9) A ninth aspect of the invention provides a sheet lamination modeling method according to the eighth aspect of the invention, wherein, in the step of hardening the melted adhesive, pressurization of the sheet lamination block is continued until the adhesive is hardened.
According to this method, the adhesive interposed between the sheets forming the finished three-dimensional object is melted and then harden while being pressurized. Thus, warps caused by such hardening or warps already generated in the object can be effectively eliminated, so that a three-dimensional object having sufficient accuracy can be obtained with ease.
(10) A tenth aspect of the invention provides a method of forming a three-dimensional object by stacking and gluing sheets together, which comprises the steps of providing a lower sheet cut into an effective area constituting the three-dimensional object and a waste area not constituting the three-dimensional object, providing an upper sheet to be stacked on top of the lower sheet, the upper sheet having an effective area constituting the three-dimensional object and a waste area not constituting the three-dimensional object, supplying an adhesive between the lower sheet and the upper sheet, gluing the lower sheet and the upper sheet together under pressure, and cutting the upper sheet into the effective area and the waste area, wherein, in the above steps, the adhesive is maintained in a melted state to thereby form a sheet lamination block including the three-dimensional object, and the sheet lamination block is pressurized until the adhesive interposed between the sheets of the sheet lamination block is hardened.
According to this method, the sheets are not glued together during stacking operation, but the sheets are stacked to form the sheet lamination block with the adhesive held in a melted state, and after completion of the stacking operation, the adhesive interposed between the sheets is hardened while being pressurized. Thus, warps by internal stress are reduced which may be generated when the adhesive is hardened during the stacking operation for each sheet, so that a three-dimensional object having sufficient accuracy can be obtained with ease.
(11) An eleventh aspect of the invention provides an apparatus for forming a three-dimensional object by stacking and gluing sheets together, which comprises a table which moves upwardly or downwardly and on which a lower sheet cut into an effective area and a waste area is placed, interposing means for interposing an adhesive between the lower sheet and an upper sheet to be stacked on the lower sheet, pressing means fixedly disposed at a predetermined position for gluing together the upper sheet and the lower sheet on the table when the table is raised, and cutting means for cutting the upper sheet into an effective area and a waste area.
According to this apparatus, by the upward or downward movement of the table acting as a sole movable part, the sheets are moved to a bonding position or to a cutting position to adjust the bonding strength or the cutting height of the cutting means, thus permitting easy fine control of the working accuracy. Therefore, adjustment depending on the change of the height of the three-dimensional object under fabrication by stacking and gluing the sheets together, can be done easily. Thus, working errors during the gluing or the cutting operation, and thus modeling errors, can be reduced.
(12) A twelfth aspect of the invention provides a sheet lamination modeling apparatus according to the eleventh aspect of the invention, wherein the table is vertically movable, the pressing means is fixedly disposed right above the table, and the cutting means is disposed horizontally movably at a predetermined height between the table in the lowered position and the pressing means.
According to this apparatus, the table acting as a sole moving part is movable only in the vertical direction, and thus the cutting height with respect to the stacked sheets can be controlled with sufficient accuracy. As a result, modeling errors can be further reduced, and a three-dimensional object having high accuracy can be obtained.
(13) A thirteenth aspect of the invention provides a sheet lamination modeling apparatus according to the eleventh aspect of the invention, wherein, as the adhesive, an adhesive which displays adhesiveness by pressurization is used, and the pressing means include a pressurization surface for collectively pressurizing the upper sheet.
According to this apparatus, the sheets are glued together by pressurization, and therefore, light exposure or like operation is not required, so that it Is possible to easily fabricate a three-dimensional object even in an ordinary office. Further, the bonding strength can be controlled by the raised position of the table.
Further, the sheets are collectively pressurized, so that the sheets and the adhesive can be formed both easily and flatly, and misalignment of the sheets can be prevented. (14) A fourteenth aspect of the invention provides a sheet lamination modeling apparatus according to the eleventh aspect of the invention, wherein the interposing means is operable to supply the adhesive onto the upper sheet by electrostatic transfer.
According to this apparatus, the adhesive is applied by electrostatic transfer, and therefore, no special means for supplying adhesive is required. Thus, it is possible to provide a simple construction of the apparatus in which an ordinary electrostatic transfer means can be utilized.
(15) A fifteenth aspect of the invention provides a sheet lamination modeling apparatus according to the eleventh aspect of the invention and further including heat retaining means for keeping warm a sheet lamination block on the table and heating means provided in the table for heating the sheet lamination block.
According to this apparatus, the adhesive interposed in the sheet lamination block is maintained in a melted state during the stacking operation, and thus, generation of warps of the sheets by hardening the adhesive between the sheets can be prevented. Further, the adhesive interposed in the sheet lamination block is melted after the stacking operation, so that any warps which may be generated during the stacking operation can be eliminated. Thus, a three-dimensional object having improved accuracy can be obtained.